Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)

The cassava whitefly (Bemisia tabaci) is a threat to cassava production as a pest and a vector of viruses that cause devastating cassava mosaic (CMD) and cassava brown streak (CBSD) diseases. The objective of this study was to evaluate the efficacy of neem oil treatments and insecticides against the...

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Autores principales: Issa, K.A., Wosula, E.N., Amour, M., Ndalahwa, M., Bruce, T., Legg, J.P.
Formato: Journal Article
Lenguaje:Inglés
Publicado: 2025
Materias:
Acceso en línea:https://hdl.handle.net/10568/178428
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author Issa, K.A.
Wosula, E.N.
Amour, M.
Ndalahwa, M.
Bruce, T.
Legg, J.P.
author_browse Amour, M.
Bruce, T.
Issa, K.A.
Legg, J.P.
Ndalahwa, M.
Wosula, E.N.
author_facet Issa, K.A.
Wosula, E.N.
Amour, M.
Ndalahwa, M.
Bruce, T.
Legg, J.P.
author_sort Issa, K.A.
collection Repository of Agricultural Research Outputs (CGSpace)
description The cassava whitefly (Bemisia tabaci) is a threat to cassava production as a pest and a vector of viruses that cause devastating cassava mosaic (CMD) and cassava brown streak (CBSD) diseases. The objective of this study was to evaluate the efficacy of neem oil treatments and insecticides against the cassava whitefly. Field plot experiments were conducted to evaluate neem oil products in 2022/2023 and neem oil combined with cutting dipping in a ‘MandiPlus’ formulation (containing Thiamethoxam, Fludioxonil & Metalaxyl-M) in 2023/2024. MandiPlus was applied once as a cutting dip at planting, while neem oil products were sprayed on a monthly basis up to 6 months after planting. The experimental design for field experiments was a randomised complete block design with four replicates. The data recorded for field experiments were on whitefly adult and nymph numbers, CMD and CBSD incidence and severity, and root yield. Neem oil treatments alone reduced whitefly adults and nymphs by 45%–70%, MandiPlus alone gave reductions of 68%–74% and MandiPlus + Neem gave a reduction of 70%. CMD (35%–54%) and CBSD (46%–100%) incidences at 6 months did not differ from control. Root yield increased by 1.8–2.0 kg/plant (78%–87%) in treatments incorporating MandiPlus, while neem oils provided a gain of 0.4–1.9 kg/plant (17%–56%). These findings confirm that the application of MandiPlus through cutting dips is effective at reducing whitefly populations and increasing yield. The application of neem oils alone conferred a significant yield gain in one season but combining with MandiPlus did not confer additive protection and yield gain. Cutting dipping in insecticides is therefore recommended for adoption as a component of integrated pest management for the control of whiteflies and the viruses that they transmit.
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spelling CGSpace1784282025-12-02T00:35:33Z Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci) Issa, K.A. Wosula, E.N. Amour, M. Ndalahwa, M. Bruce, T. Legg, J.P. bemisia tabaci cassava brown streak disease african cassava mosaic virus insecticides neem cassava manihot esculenta The cassava whitefly (Bemisia tabaci) is a threat to cassava production as a pest and a vector of viruses that cause devastating cassava mosaic (CMD) and cassava brown streak (CBSD) diseases. The objective of this study was to evaluate the efficacy of neem oil treatments and insecticides against the cassava whitefly. Field plot experiments were conducted to evaluate neem oil products in 2022/2023 and neem oil combined with cutting dipping in a ‘MandiPlus’ formulation (containing Thiamethoxam, Fludioxonil & Metalaxyl-M) in 2023/2024. MandiPlus was applied once as a cutting dip at planting, while neem oil products were sprayed on a monthly basis up to 6 months after planting. The experimental design for field experiments was a randomised complete block design with four replicates. The data recorded for field experiments were on whitefly adult and nymph numbers, CMD and CBSD incidence and severity, and root yield. Neem oil treatments alone reduced whitefly adults and nymphs by 45%–70%, MandiPlus alone gave reductions of 68%–74% and MandiPlus + Neem gave a reduction of 70%. CMD (35%–54%) and CBSD (46%–100%) incidences at 6 months did not differ from control. Root yield increased by 1.8–2.0 kg/plant (78%–87%) in treatments incorporating MandiPlus, while neem oils provided a gain of 0.4–1.9 kg/plant (17%–56%). These findings confirm that the application of MandiPlus through cutting dips is effective at reducing whitefly populations and increasing yield. The application of neem oils alone conferred a significant yield gain in one season but combining with MandiPlus did not confer additive protection and yield gain. Cutting dipping in insecticides is therefore recommended for adoption as a component of integrated pest management for the control of whiteflies and the viruses that they transmit. 2025 2025-12-02T00:35:32Z 2025-12-02T00:35:32Z Journal Article https://hdl.handle.net/10568/178428 en Limited Access Issa, K.A., Wosula, E.N., Amour, M., Ndalahwa, M., Bruce, T. & Legg, J.P. (2025). Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci). Journal of Applied Entomology, 1-11.
spellingShingle bemisia tabaci
cassava brown streak disease
african cassava mosaic virus
insecticides
neem
cassava
manihot esculenta
Issa, K.A.
Wosula, E.N.
Amour, M.
Ndalahwa, M.
Bruce, T.
Legg, J.P.
Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title_full Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title_fullStr Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title_full_unstemmed Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title_short Efficacy of neem oil sprays and thiamethoxam-metalaxyl cutting dips in the management of cassava whitefly (Bemisia tabaci)
title_sort efficacy of neem oil sprays and thiamethoxam metalaxyl cutting dips in the management of cassava whitefly bemisia tabaci
topic bemisia tabaci
cassava brown streak disease
african cassava mosaic virus
insecticides
neem
cassava
manihot esculenta
url https://hdl.handle.net/10568/178428
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